James Mangold on Wolverine's X-Men: Days of Future Past credits scene

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The Wolverine director James Mangold has spoken to Digital Spy about the film's mid-credits scene that teases next year's X-Men: Days of Future Past.

Mangold revealed that the sequence - showing Hugh Jackman's Logan meeting Ian McKellen's Magneto and Patrick Stewart's Professor X at an airport - was shot after he wrapped production on The Wolverine.

"I had finished the movie and Future Past had started shooting, a couple months ago, and we had been talking about what to do, if anything, in the tail credits of this movie," Mangold said.

"It's something I had been talking about with Simon Kinberg (X-Men producer) and Bryan Singer at that point about what we might do to kind of feed into it. My only stipulation that was important to me was just that I really didn't want it to be tongue-in-cheek. I feel like a lot of these bonus things almost make the film into a joke, and that wasn't interesting to me.

"I thought it would be more interesting to try and actually do something quite promising, actually say something and promise something and give people a piece of a story."

Mangold added that it was "a thrill" to work with McKellen and Stewart, who will both return for Days of Future Past.

"The whole sequence was built around the shot where we'd unveil Patrick, and I created this shot where he's weaving through all these frozen airport patrons and that is Patrick Stewart with a joystick and electric wheelchair and that isn't easy," he explained.

"He's doing a kind of Olympic slalom through all these extras and he's a badass on that thing."

Asked if he was glad that it would be Singer's job to fully explain how Stewart's Charles Xavier is alive after the events of X-Men: The Last Stand, Mangold quipped: "Yes, it is his job and I know they have one, so I'll leave it to them to unveil it."

The Wolverine is showing in cinemas now. X-Men: Days of Future Past will open in May 2014.